Environment controllers are used in building automation and industrial environments to control one or a plurality of environment conditions. Environment controllers receive measurements performed by one or several sensors in an area of the building, and correspondingly instruct an equipment to perform an instruction so as to change the environment condition. One environment controller may control one or several equipment for an area of the building.
Typical implementations require the use of several environment controllers to control one of a plurality of environment conditions for an area of a building (such as for example a room, a subset of rooms, a floor, an aisle, etc.). There is therefor a need to use multiple environment controllers concurrently.
Each environment controller requires power to function. UL standards define various classes of power units, including class 2 power units for indoor and outdoor power supplies and battery chargers. Class 2 is particularly interesting, as it requires an isolating transformer, and limits the output voltages to 42.4 V peak for alternating current or 60V for continuous direct current with a transformer capacity of a maximum of 100VA Class 2 power supplies are safely used and installed without requiring the involvement of electricians. Other standards similarly define power supplies specifications and requirements.
Output voltages of up to 42.4V peak for alternating current are often referred as low-voltage. Low voltages are typically less dangerous than higher voltages. However, low-voltage power supplies typically suffer from a relatively low electrical power factor, i.e. the useful power output/total apparent power input.
Low electrical power factor may be acceptable for stand-alone power supplies. However, low electrical power factor seriously affects equipment connected in a daisy-chained power configuration, such as for example environment controllers.
There is therefore a need for a low-voltage daisy-chainable environment controller with improved electrical power factor.